Volume Solution7





In this page volume solution7 we are going to see solution of each questions of the worksheet volume worksheet2.

Question 15:

The volume of a cone with circular base is 216 Π cu.cm. If the base radius is 9 cm,then find the height of the cone.

Solution:

Volume of the cone = 216 Π cu.cm

Radius of the cone = 9 cm

(1/3) Π r² h = 216 Π

           (9)² h = 216 x 3

            h = 216 x 3 x (1/9) (1/9)

            h = 24/3

            h = 8 cm

Required height of cone = 8 cm


Question 16:

Find the mass of 200 steel spherical ball bearings,each of which has radius 0.7 cm, given that the density of steel is 7.95 g/cm³. (Mass = Volume x Density)

Solution:

radius of spherical ball = 0.7 cm 

Volume of one spherical ball = (4/3) Π r³

                                         = (4/3) (22/7) (0.7) (0.7)(0.7)

                                         = (4/3) (22) (0.1) (0.7)(0.7)

                                         = 4.312/3

                                         = 1.437

Volume of 200 steel spherical ball = 200 x 1.437

                                                = 287.46 cm³

1 cm³ = 7.95 g

Therefore mass of 200 spherical ball bearings = 287.46 x 7.95

                                                                 = 2285.307 gram

1000 gram = 1 kg

                 = 2285.307/1000

                 = 2.29 kg

Volume of 200 spherical balls = 2.29 kg


Question 17:

The outer and inner radii of a hollow sphere are 12 cm and 10 cm. Find its volume.

Solution:

From this information we have to find the volume

Outer radius (R) =  12 cm

Inner radius (r) = 10 cm

Volume of hollow sphere = (4/3) Π (R³ - r³)

                                    = (4/3)(22/7) (12³ - 10³)

                                    = (88/21) (1728 - 1000)

                                    = (88/21) (728)

                                    = (64064/21)

                                    = 3050.67 cm³

Volume of hollow sphere = 3050.67 cm³

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